R&S®SMBVB-K548
Crest Factor Reduction
User Manual
1179092202
Version 05
(;Ý9F2)
This document describes the following software options:
●R&S®SMBVB-K548 Crest Factor Reduction (1423.8820.xx)
This manual describes firmware version FW 5.30.047.xx and later of the R&S®SMBV100B.
© 2023 Rohde & Schwarz
Muehldorfstr. 15, 81671 Muenchen, Germany
Phone: +49 89 41 29 - 0
Email: [email protected]
Internet: www.rohde-schwarz.com
Subject to change – data without tolerance limits is not binding.
R&S® is a registered trademark of Rohde & Schwarz GmbH & Co. KG.
All other trademarks are the properties of their respective owners.
1179.0922.02 | Version 05 | R&S®SMBVB-K548
The following abbreviations are used throughout this manual: R&S®SMBV100B is indicated as R&S SMBVB; the license types
02/03/07/11/13/16/12 are abbreviated as xx.
Contents
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3User Manual 1179.0922.02 ─ 05
Contents
1 Welcome to the R&S SMBVB-K548 option.......................................... 5
1.1 Accessing Crest Factor Reduction settings...............................................................5
1.2 What's new.....................................................................................................................5
1.3 Documentation overview..............................................................................................6
1.3.1 Getting started manual....................................................................................................6
1.3.2 User manuals and help................................................................................................... 6
1.3.3 Service manual............................................................................................................... 6
1.3.4 Instrument security procedures.......................................................................................7
1.3.5 Printed safety instructions............................................................................................... 7
1.3.6 Data sheets and brochures............................................................................................. 7
1.3.7 Release notes and open source acknowledgment (OSA).............................................. 7
1.3.8 Application notes, application cards, white papers, etc...................................................7
1.3.9 Videos............................................................................................................................. 7
1.4 Scope............................................................................................................................. 8
1.5 Notes on screenshots...................................................................................................8
2 About the crest factor reduction.......................................................... 9
3 Crest factor reduction settings...........................................................11
4 Remote-control commands.................................................................16
List of commands................................................................................ 24
Index......................................................................................................25
Contents
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4User Manual 1179.0922.02 ─ 05
Welcome to the R&S SMBVB-K548 option
R&S®SMBVB-K548
5User Manual 1179.0922.02 ─ 05
1 Welcome to the R&S SMBVB-K548 option
The R&S SMBVB-K548 is a software option that allows you to generate signals with
reduced crest factor.
R&S SMBVB-K548 key features
●Reduces the crest factor of a baseband signal through clipping the high signal
peaks and filtering the waveform afterwards.
●Can be applied to any waveform file loaded in the arbitrary waveform generator.
●It uses an iterative process to reach the desired crest factor delta.
●It is possible to adjust the filter characteristics. In simple mode, you can specify the
channel spacing and signal bandwidth. Alternatively in the advanced filter mode
you can specify the lowpass filter through passband and stopband frequencies.
This user manual contains a description of the functionality that the application pro-
vides, including remote control operation.
All functions not discussed in this manual are the same as in the base unit and are
described in the R&S SMBV100B user manual. The latest version is available at:
www.rohde-schwarz.com/manual/SMBV100B
Installation
You can find detailed installation instructions in the delivery of the option or in the
R&S SMBV100B service manual.
1.1 Accessing Crest Factor Reduction settings
1. In the block diagram of the R&S SMBV100B, select the "Baseband" > "ARB".
The "ARB" dialog box opens and provides general "ARB" settings.
2. Select "Crest Factor Reduction".
The signal generation is not started immediately. To reduce crest factors with the
default settings, see "Activating crest factor reduction" on page 11.
1.2 What's new
This manual describes firmware version FW 5.30.047.xx and later of the
R&S®SMBV100B.
What's new
Welcome to the R&S SMBVB-K548 option
R&S®SMBVB-K548
6User Manual 1179.0922.02 ─ 05
Compared to the previous version, it provides peak cancellation algorithm for crest fac-
tor reduction:
●Background information on the algorithm "Peak cancellation algorithm"
on page 9
●Algorithm settings, see "Algorithm" on page 12, "Cancellation Pulse Bandwidth"
on page 15 and "Transition Bandwidth" on page 15
1.3 Documentation overview
This section provides an overview of the R&S SMBV100B user documentation. Unless
specified otherwise, you find the documents at:
www.rohde-schwarz.com/manual/smbv100b
1.3.1 Getting started manual
Introduces the R&S SMBV100B and describes how to set up and start working with the
product. Includes basic operations, typical measurement examples, and general infor-
mation, e.g. safety instructions, etc. A printed version is delivered with the instrument.
1.3.2 User manuals and help
Separate manuals for the base unit and the software options are provided for down-
load:
●Base unit manual
Contains the description of all instrument modes and functions. It also provides an
introduction to remote control, a complete description of the remote control com-
mands with programming examples, and information on maintenance, instrument
interfaces and error messages. Includes the contents of the getting started manual.
●Software option manual
Contains the description of the specific functions of an option. Basic information on
operating the R&S SMBV100B is not included.
The contents of the user manuals are available as help in the R&S SMBV100B. The
help offers quick, context-sensitive access to the complete information for the base unit
and the software options.
All user manuals are also available for download or for immediate display on the Inter-
net.
1.3.3 Service manual
Describes the performance test for checking compliance with rated specifications, firm-
ware update, troubleshooting, adjustments, installing options and maintenance.
Documentation overview
Welcome to the R&S SMBVB-K548 option
R&S®SMBVB-K548
7User Manual 1179.0922.02 ─ 05
The service manual is available for registered users on the global Rohde & Schwarz
information system (GLORIS):
https://gloris.rohde-schwarz.com
1.3.4 Instrument security procedures
Deals with security issues when working with the R&S SMBV100B in secure areas. It
is available for download on the internet.
1.3.5 Printed safety instructions
Provides safety information in many languages. The printed document is delivered with
the product.
1.3.6 Data sheets and brochures
The data sheet contains the technical specifications of the R&S SMBV100B. It also
lists the options and their order numbers and optional accessories.
The brochure provides an overview of the instrument and deals with the specific char-
acteristics.
See www.rohde-schwarz.com/brochure-datasheet/smbv100b
1.3.7 Release notes and open source acknowledgment (OSA)
The release notes list new features, improvements and known issues of the current
firmware version, and describe the firmware installation.
The software makes use of several valuable open source software packages. An open-
source acknowledgment document provides verbatim license texts of the used open
source software.
See www.rohde-schwarz.com/firmware/smbv100b
1.3.8 Application notes, application cards, white papers, etc.
These documents deal with special applications or background information on particu-
lar topics.
See www.rohde-schwarz.com/application/smbv100b
1.3.9 Videos
Find various videos on Rohde & Schwarz products and test and measurement topics
on YouTube: https://www.youtube.com/@RohdeundSchwarz
Documentation overview
Welcome to the R&S SMBVB-K548 option
R&S®SMBVB-K548
8User Manual 1179.0922.02 ─ 05
On the menu bar, search for your product to find related videos.
Figure 1-1: Product search on YouTube
1.4 Scope
Tasks (in manual or remote operation) that are also performed in the base unit in the
same way are not described here.
In particular, it includes:
●Managing settings and data lists, like saving and loading settings, creating and
accessing data lists, or accessing files in a particular directory.
●Information on regular trigger, marker and clock signals and filter settings, if appro-
priate.
●General instrument configuration, such as checking the system configuration, con-
figuring networks and remote operation
●Using the common status registers
For a description of such tasks, see the R&S SMBV100B user manual.
1.5 Notes on screenshots
When describing the functions of the product, we use sample screenshots. These
screenshots are meant to illustrate as many as possible of the provided functions and
possible interdependencies between parameters. The shown values may not represent
realistic usage scenarios.
The screenshots usually show a fully equipped product, that is: with all options instal-
led. Thus, some functions shown in the screenshots may not be available in your par-
ticular product configuration.
Notes on screenshots
About the crest factor reduction
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9User Manual 1179.0922.02 ─ 05
2 About the crest factor reduction
Communication standards utilizing higher order modulation techniques or using multi-
ple carrier and complex signals consisting of the signals of more than one digital stan-
dard can feature a high crest factor. The signals of some digital standards can have
high crest factors also particularly with many channels and long sequences.
About crest factors
The crest factor represents the ratio of the peak voltage value to the RMS voltage
value, i.e. the peak to average ratio (PAR). The higher the crest factor and the resulting
dynamics of a signal, the greater the requirement for a power amplifier fed by the sig-
nal to be linear.
A high crest factor arises, for example, for a multi carrier signal that has carriers with
an identical start phase. The carriers are periodically superposed that leads to high
peak voltages in relation to the RMS voltage values.
High crest factors entail two basic problems:
●The nonlinearity of the power amplifier (compression) causes intermodulation
which expands the spectrum (spectral regrowth).
●Since the level of the digital to analog (D/A) converter is relative to the maximum
value, the average value is converted with a relatively low resolution. This low res-
olution leads to a high quantization noise.
Both effects increase the adjacent-channel power.
Clipping and filtering algorithm
A common and simple approach for achieving a lower PAR is the combination of clip-
ping and filtering.
●Clipping is a technique that applies a wanted distortion to the signal.
The principle includes specifying a threshold, finding out the signal peaks once the
defined limits are exceeded and clipping them off. The level limit is specified as a
percentage of the highest peak value. Because clipping is done before filtering, the
procedure does not influence the spectrum. The error vector magnitude (EVM)
however increases.
However, signal clipping not only changes the peak value but also the average
value and the effect on the crest factor is unpredictable.
●Filtering is applied after clipping. The used filters are specially designed so that
they filter out the distortion.
Peak cancellation algorithm
The peak cancellation algorithm uses Blackman windowed sinc pulses and subtracts
them from the original baseband signal wherever the signal amplitude exceeds a
defined threshold. This threshold equals maximum peak of the baseband signal minus
a user-definable crest factor difference ("Desired Crest Factor Delta").
This algorithm often provides better EVM results of the output signal versus out of
band noise introduced by the pulses, compared to the clipping and filtering method.
About the crest factor reduction
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10User Manual 1179.0922.02 ─ 05
The cancellation pulse bandwidth is configurable and the cancellation pulse transition
bandwidth. The achieved resulting crest factor can be higher than expected, because
of filters in the signal processing chain increasing the crest factor again after a previous
crest factor reduction.
Crest factor reduction settings
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3 Crest factor reduction settings
Access:
► Select "Baseband" > "ARB" > "Crest Factor Reduction".
The dialog provides settings to configure and activate crest factor reduction.
Activating crest factor reduction
Crest factor reduction requires an active "ARB" state and a valid waveform file loaded
to the ARB application.
1. Load a waveform file.
a) Select "ARB" > "General" > "Load Waveform".
b) In the file-select dialog, select the waveform file from the directory.
See also chapter "How to load and play waveform files" in the R&S SMBV100B
user manual.
2. Select "General" > "State" > "On".
3. Select "Crest Factor Reduction" > "State" > "On".
The remote commands required to define these settings are described in Chapter 4,
"Remote-control commands", on page 16.
Settings:
State..............................................................................................................................12
Generate Waveform...................................................................................................... 12
Algorithm....................................................................................................................... 12
Desired Crest Factor Delta............................................................................................12
Max Iterations................................................................................................................12
Original Crest Factor..................................................................................................... 13
Resulting Crest Factor.................................................................................................. 13
Filter Mode.................................................................................................................... 13
Channel Spacing...........................................................................................................14
Crest factor reduction settings
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Signal Bandwidth.......................................................................................................... 14
Stopband Frequency.....................................................................................................14
Passband Frequency.................................................................................................... 14
Maximum Filter Order................................................................................................... 15
Cancellation Pulse Bandwidth.......................................................................................15
Transition Bandwidth.....................................................................................................15
State
Requires an active "ARB" state, see "Activating crest factor reduction" on page 11.
Activates crest factor reduction calculation.
Note: You cannot activate the crest factor reduction and the notch filter simultaneously.
Enabling the notched filter automatically disables the crest factor reduction.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR[:STATe] on page 18
Generate Waveform
With enabled signal generation, triggers the instrument to save the current settings of
an arbitrary waveform signal in a waveform file with predefined extension *.wv. You
can define the filename and the directory, in that you want to save the file.
Using the ARB modulation source, you can play back waveform files and/or process
the file to generate multi-carrier or multi-segment signals.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:WAVeform:CREate on page 22
Algorithm
Defines the algorithm for crest factor reduction.
"Clipping and Filtering"
This algorithm performs a hard clipping. It is followed by a low pass
filtering of the result in an iterative manner until the target crest factor
is reached. You can define the settings of the filter that is used for the
calculation.
"Peak Cancelation"
This algorithm subtracts Blackman windowed sinc pulses from the
signal wherever the amplitude is above a defined threshold.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:ALGorithm on page 18
Desired Crest Factor Delta
Sets the value difference by which you want to change your crest factor.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:DCFDelta on page 19
Max Iterations
Requires "Algorithm" > "Clipping and Filtering".
Sets the number of iterations that are used for calculating the resulting crest factor. The
iteration process is stopped when the desired crest factor delta is achieved by 0.1 dB.
Crest factor reduction settings
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13User Manual 1179.0922.02 ─ 05
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:ITERations on page 20
Original Crest Factor
Displays the original crest factor of the waveform after the calculation of the resulting
crest factor is completed. The original crest factor is calculated as an average over the
whole waveform, including any idle periods that can be present in TDD waveforms.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:OCFactor? on page 20
Resulting Crest Factor
Displays the resulting crest factor of the waveform after the calculations are completed.
The resulting crest factor is calculated as an average over the whole waveform, includ-
ing any idle periods that can be present in TDD waveforms.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:RCFactor? on page 21
Filter Mode
Requires "Algorithm" > "Clipping and Filtering".
Selects which filter mode is used for the filtering.
"Simple" You can specify the RF bandwidth and channel spacing of the signal.
The lowpass filter is designed to pass through frequency components
inside the signal bandwidth and suppress components in the adjacent
channel.
Figure 3-1: Simple filter mode
Crest factor reduction settings
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"Enhanced" In the enhanced filter mode, you can specify the passband and stop-
band frequencies of the lowpass filter.
Figure 3-2: Enhanced filter mode
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:FILTer on page 19
Channel Spacing
Requires "Algorithm" > "Clipping and Filtering" and "Filter Mode" > "Simple".
Sets the channel spacing.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:CSPacing on page 19
Signal Bandwidth
Requires "Algorithm" > "Clipping and Filtering" and "Filter Mode" > "Simple".
Sets the signal bandwidth. Set a value that is lower than the value of the "Channel
Spacing".
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:SBANdwidth on page 21
Stopband Frequency
Requires "Algorithm" > "Clipping and Filtering" and "Filter Mode" > "Enhanced".
Sets the stopband frequency of the filter. Frequency components higher than the stop-
band frequency are filtered out by the lowpass filter.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:SFReq on page 22
Passband Frequency
Requires "Algorithm" > "Clipping and Filtering" and "Filter Mode" > "Enhanced".
Sets the passband frequency. Frequency components lower than the passband fre-
quency are passed through unfiltered.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:PFReq on page 21
Crest factor reduction settings
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Maximum Filter Order
Requires "Algorithm" > "Clipping and Filtering" and "Filter Mode" > "Enhanced".
Sets the maximum filter order.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:FORDer on page 19
Cancellation Pulse Bandwidth
Requires "Algorithm" > "Peak Cancellation".
Sets the bandwidth of the cancellation pulse.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:CPBandwidth on page 18
Transition Bandwidth
Requires "Algorithm" > "Peak Cancellation".
Sets the transition bandwidth of the cancellation pulse.
Remote command:
[:SOURce<hw>]:BB:ARBitrary:CFR:TBANdwidth on page 22
Remote-control commands
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4 Remote-control commands
The following commands are required to perform signal generation in a remote envi-
ronment. We assume that the R&S SMBV100B has already been set up for remote
operation in a network as described in the R&S SMBV100B user manual. Knowledge
about the remote control operation and the SCPI command syntax is assumed.
Conventions used in SCPI command descriptions
For a description of the conventions used in the remote command descriptions, see
section "Remote Control Commands" in the R&S SMBV100B user manual.
Common suffixes
The following common suffixes are used in remote commands:
Suffix Value range Description
SOURce<hw> 1 Available baseband signals
Programming examples
The corresponding sections of the same title provide simple programming examples for
the R&S SMBV100B. The purpose of the examples is to present all commands for a
given task. In real applications, one would rather reduce the examples to an appropri-
ate subset of commands.
The programming examples have been tested with a software tool which provides an
environment for the development and execution of remote tests. To keep the examples
as simple as possible, only the "clean" SCPI syntax elements are reported. Non-exe-
cutable command lines (e.g. comments) start with two // characters.
At the beginning of the most remote control program, an instrument (p) reset is recom-
mended to set the R&S SMBV100B to a definite state. The commands *RST and
SYSTem:PRESet are equivalent for this purpose. *CLS also resets the status registers
and clears the output buffer.
Example: Preparing for CFR
// Load an ARB waveform file, e.g., the file "test.wv".
SOURce1:BB:ARBitrary:LOAD "test"
// Activate ARB.
SOURce1:BB:ARBitrary:STATe 1
Example: Applying clipping and filtering algorithm
// Set for filter and clipping CFR algorithm.
SOURce1:BB:ARBitrary:CFR:ALGorithm CLFiltering
SOURce1:BB:ARBitrary:CFR:DCFDelta -3
SOURce1:BB:ARBitrary:CFR:ITERations 5
Remote-control commands
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// Configure simple filtering.
SOURce1:BB:ARBitrary:CFR:FILTer SIMPle
SOURce1:BB:ARBitrary:CFR:CSPacing 20E6
SOURce1:BB:ARBitrary:CFR:SBANdwidth 18E6
// Configure enhanced filtering.
SOURce1:BB:ARBitrary:CFR:FILTer ENHanced
SOURce1:BB:ARBitrary:CFR:PFReq 9E6
SOURce1:BB:ARBitrary:CFR:SFReq 11E6
SOURce1:BB:ARBitrary:CFR:FORDer 100
Example: Applying peak cancellation algorithm
// Set for peak cancellation CFR algorithm.
SOURce1:BB:ARBitrary:CFR:ALGorithm PCANcellation
SOURce1:BB:ARBitrary:CFR:DCFDelta -3
// Set a cancellation pulse bandwidth of 800 kHz.
SOURce1:BB:ARBitrary:CFR:CPBandwidth 800000
// Set a transition bandwidth of 10 kHz.
SOURce1:BB:ARBitrary:CFR:TBANdwidth 10000
Example: Activating and monitoring CFR characteristics
SOURce1:BB:ARBitrary:CFR:STATe 1
SOURce1:BB:ARBitrary:CFR:MEASure:STATe?
// Response: "1"
// Query the original crest factor.
SOURce1:BB:ARBitrary:CFR:OCFactor?
// Response: "6"
// Query the resulting crest factor.
SOURce1:BB:ARBitrary:CFR:RCFactor?
// Response: "3"
// Create the waveform file "cfr.wv" with reduced crest factor.
SOURce1:BB:ARBitrary:CFR:CREate "cfr"
The commands specific to the Crest Factor Reduction option are described here:
Commands
[:SOURce<hw>]:BB:ARBitrary:CFR[:STATe]....................................................................... 18
[:SOURce<hw>]:BB:ARBitrary:CFR:ALGorithm...................................................................18
[:SOURce<hw>]:BB:ARBitrary:CFR:CPBandwidth...............................................................18
[:SOURce<hw>]:BB:ARBitrary:CFR:CSPacing.................................................................... 19
[:SOURce<hw>]:BB:ARBitrary:CFR:DCFDelta.................................................................... 19
[:SOURce<hw>]:BB:ARBitrary:CFR:FILTer......................................................................... 19
[:SOURce<hw>]:BB:ARBitrary:CFR:FORDer...................................................................... 19
[:SOURce<hw>]:BB:ARBitrary:CFR:ITERations.................................................................. 20
[:SOURce<hw>]:BB:ARBitrary:CFR:MEASure[:STATe]?.......................................................20
[:SOURce<hw>]:BB:ARBitrary:CFR:OCFactor?...................................................................20
[:SOURce<hw>]:BB:ARBitrary:CFR:PFReq........................................................................ 21
[:SOURce<hw>]:BB:ARBitrary:CFR:RCFactor?...................................................................21
[:SOURce<hw>]:BB:ARBitrary:CFR:SBANdwidth................................................................ 21
Remote-control commands
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[:SOURce<hw>]:BB:ARBitrary:CFR:SFReq........................................................................ 22
[:SOURce<hw>]:BB:ARBitrary:CFR:TBANdwidth................................................................ 22
[:SOURce<hw>]:BB:ARBitrary:CFR:WAVeform:CREate....................................................... 22
[:SOURce<hw>]:BB:ARBitrary:CFR[:STATe] <ArbCfrState>
Enables the crest factor reduction calculation.
Parameters:
<ArbCfrState> 1 | ON | 0 | OFF
*RST: 0
Example: See Example"Activating and monitoring CFR characteristics"
on page 17.
Manual operation: See "State" on page 12
[:SOURce<hw>]:BB:ARBitrary:CFR:ALGorithm <ArbCfrAlgorithm>
Defines the algorithm for crest factor reduction.
Parameters:
<ArbCfrAlgorithm> CLFiltering | PCANcellation
CLFiltering
Clipping and filtering algorithm. This algorithm performs a hard
clipping of the baseband signal. It is followed by a low pass filter-
ing of the result in an iterative manner until the target crest factor
is reached. You can define the settings of the filter that is used
for the calculation.
PCANcellation
Peak cancelation algorithm. This algorithm subtracts Blackman
windowed sinc pulses from the signal wherever the amplitude is
above a defined threshold.
*RST: CLFiltering
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Example: See Example"Applying peak cancellation algorithm" on page 17.
Manual operation: See "Algorithm" on page 12
[:SOURce<hw>]:BB:ARBitrary:CFR:CPBandwidth <ArbCfrCancPulBw>
Sets the cancellation pulse bandwidth for peak cancellation CFR algorithm.
Parameters:
<ArbCfrCancPulBw> float
Range: 0 to 250E6
Increment: 0.1
Example: See Example"Applying peak cancellation algorithm" on page 17.
Remote-control commands
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Manual operation: See "Cancellation Pulse Bandwidth" on page 15
[:SOURce<hw>]:BB:ARBitrary:CFR:CSPacing <ArbCfrChanSpac>
Sets the channel spacing, if [:SOURce<hw>]:BB:ARBitrary:CFR:FILTer is set to
SIMPle.
Parameters:
<ArbCfrChanSpac> float
Range: 0 to depends on the sample rate of the loaded file
Increment: 0.1
*RST: 250E6
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Manual operation: See "Channel Spacing" on page 14
[:SOURce<hw>]:BB:ARBitrary:CFR:DCFDelta <ArbCfrDCFDelta>
Sets the value difference by which you want to change your crest factor.
Parameters:
<ArbCfrDCFDelta> float
Range: -20 to 0
Increment: 0.1
*RST: -3
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Manual operation: See "Desired Crest Factor Delta" on page 12
[:SOURce<hw>]:BB:ARBitrary:CFR:FILTer <ArbCfrFilterMod>
Selects which filter mode is used for the filtering.
Parameters:
<ArbCfrFilterMod> SIMPle | ENHanced
*RST: SIMPle
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Manual operation: See "Filter Mode" on page 13
[:SOURce<hw>]:BB:ARBitrary:CFR:FORDer <ArbCfrMaxFilOrd>
Sets the maximum filter order, if [:SOURce<hw>]:BB:ARBitrary:CFR:FILTer is
set to ENHanced.
Remote-control commands
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Parameters:
<ArbCfrMaxFilOrd> integer
Range: 0 to 300
*RST: 100
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Manual operation: See "Maximum Filter Order" on page 15
[:SOURce<hw>]:BB:ARBitrary:CFR:ITERations <ArbCfrMaxIter>
Sets the number of iterations that are used for calculating the resulting crest factor. The
iteration process is stopped when the desired crest factor delta is achieved by 0.1 dB.
Parameters:
<ArbCfrMaxIter> integer
Range: 1 to 10
*RST: 5
Example: See Example"Applying clipping and filtering algorithm"
on page 16.
Manual operation: See "Max Iterations" on page 12
[:SOURce<hw>]:BB:ARBitrary:CFR:MEASure[:STATe]?
Queries the state of the crest factor reduction calculation.
Return values:
<MeasureState> 1 | ON | 0 | OFF
ON: the original and resulting crest factors are already calcula-
ted.
*RST: 0
Example: See Example"Activating and monitoring CFR characteristics"
on page 17.
Usage: Query only
[:SOURce<hw>]:BB:ARBitrary:CFR:OCFactor?
Queries the original crest factor of the waveform after the calculation of the resulting
crest factor is completed. The original crest factor is calculated as an average over the
whole waveform, including any idle periods that might be present in TDD waveforms.
Return values:
<ArbCfrOCrestFac> float
Range: 1 to 100
Increment: 0.01
*RST: 6
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Rohde&Schwarz SMM100A User manual
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